The overall objectives of this proposal are the development and validation of an index of injury/illness severity as an operational tool for emergency medical care evaluation. Data elements judged likely to influence patients outcome and outcome data will be abstracted from ambulance report forms and emergency departments (ED) records by research assistants at at least four hospitals. Following statistical analysis and review by a panel of experts, those elements which reflect change in patient status and are practical to assess on patient arrival and departure will be included in a large scale data collection. Analysis relating these signs, symptoms and medical history information to actual patient outcomes will be used to develop a severity index consisting only of data predictive of patient outcome. The severity index will then be tested operationally by EMT's and E.D. personnel. When assessed at several points during the emergency care process, the severity index will serve as a surrogate outcome measure and will thus enable future evaluation efforts to determine the efficacy of specific medical care and system process measures.